This application relates to a unique hub cap used in wheel end assembly for a tire inflation system. The hub cap includes an internal filtering system for removing contaminants from the air supply before entering the tires.
Tire inflation systems automatically supply air to tires when certain predetermined conditions are met. In a typical situation, the tire inflation system will automatically add air to a tire that becomes under-inflated during vehicle operation. Tire inflation systems include sensors and pressure regulators for monitoring the pressure in each of the vehicle's tires. When pressure in any tire drops below a predetermined level, the system automatically supplies air to that tire until a desired pressure is achieved.
Some systems include check valves for permitting one way air flow, i.e., air flow from the air supply to the tire, so that unwanted tire deflation does not occur. Other systems include valves for permitting two way air flow, i.e. air flow into and out of the tires, so that variable tire pressures can be achieved depending upon the type of terrain over which the vehicle will travel. For example, on hard surfaces such as packed dirt or concrete a higher tire pressure is preferred whereas on surfaces such as sand or mud a lower tire pressure is preferred for increased traction. Usually the tire inflation systems also include an unloader valve that prevents air from being supplied to a tire if there is a blowout.
The tire inflation systems include an air tank that is mounted on the vehicle. Air is supplied from the tank to the tires by using various methods. All inflation systems must include a rotary connection that allows air to be supplied to the tires during rotation. Some systems include a rotary valve mounted on one end of the axle. In theses systems, air is supplied from the tank to the interior of the axle. Air from inside the axle passes through the rotary valve and is conducted to the tires. Another system supplies air via a hub that is rotatable supported on the axle. Rotary seals are used to provide a sealed environment for air conduction.
When vehicles operate off-road under severe conditions, the air supply can become easily contaminated with dirt particles and other debris, which can clog air supply system components. Air filtering systems are required to remove any contaminants from the air before entering the tires. Current air filters are located with the axle housing. This location is undesirable because it is difficult to replace and/or remove the filters.
Thus, it is desirable to have a wheel end assembly for a tire inflation system that provides a simplified air filtering system that can be easily installed and which utilizes an air filter that is easily accessible for removal, replacement, or cleaning.